2016 CX-9 AC Leak (suspecting upper suction line)


2016 Mazda 2016

Thought I'd ask real quick if anyone has had similar issues? Went on a 5 hour trip a week ago and found our AC wasn't working. Got to our hotel, could tell the compressor wasn't kicking on at all. So I took off the valve caps off and depressed both and....nothing. Knew at that point we had a leak somewhere.

So to give a little context, we had our engine replaced a year and a half ago. Then this past December had to have the trans and engine "recracked" apart to have the flywheel bolts sealed which was not done when the engine job took place. I guess what I was wondering is, where would the AC be taken apart at when the engine job is done...any ideas. Would they just leave the compressor on the car and the system intact (hang the compressor off to the side), or would they vacuum the system and refill it? The reason I ask, is I bought a freon "sniffer" and I am getting a leak detected on the upper suction line connection right behind the schrader valve, at that connection seam. It seems the leak "spewed" onto the foam coverings near the connection because the sniffer picks that up too on them. So I guess what I am asking, do you think this is a leak, maybe it was disturbed this past time when the car was worked on? Have any of you had a similar issue? The O-ring was completely dry when I took the hose apart, no oil or residue...dry as a bone.

Just thought I'd ask. I bought a vacuum and o-ring kits to see if this is the culprit. Hoping this is it, because it would be super simple being the location of this connection. Thought I'd replace the o-ring and then vacuum it down and see if it holds for an extended period of time before throwing more freon in it.

Also, if I do this, do I need to worry about the pag oil type. Would there still be oil in the system? I didn't see anything saturated near that connection.

Hope some of you all can give me some help/insight on this.

Thanks everyone
Probably should have stated that it worked after the engine replacement. That’s kind of why I was asking opinion on this. It worked for about a year and now all of a sudden has no Freon.

I would venture to say(or believe) after this past go around in December when they sealed the crank bolts is when something happened.

The Compressor isn’t kicking on at this point because it’s not holding pressure, so dye won’t migrate the system. The sniffer I bought immediately caught the leak around that connection block right behind the low side Schrader valve. I’ve not detected anything else at this point, and Ive spent a solid 45 minutes going over everything I could. I’m going to try and see if an oring replacement helps hold vacuum before I do anything else at this point.

But to your point, short of jumping the compressor to get the dye to flow (which will probably be my next step) I don’t know what else to do at this point. The system has no pressure in it.
I would do as you suggested. Replace o-ring and pull a vacuum to check for leaks. When recharged retest with sniffer. I would also add 1oz og Pag oil to replace ant lost in leak. A compressor running low on refrigerant tends to not return oil to the compressor.
Damn! Haven't seen that TSB yet, so thank you. Just when I thought this car was done bending me over. I'll have to check it out when I get home tonight. Looks as if I might be pulling the undercover....again!

Were you able to see any of the leaking from looking into the front of the bumper by chance? I'm suspecting not, but just thought I'd ask.

Also, the pag oil listed is a bit odd on the sticker on the front as I can't find anything on the net. Does this convert to something else. It says SAE J639 on the sticker.

Thanks again guys for the help so far! Much appreciated!
I didn’t check to be honest. The compressor was making a very small noise and then stopped. And a few days later it got warm enough for me to test if the AC was working and i wouldn’t get any cold air. I am in Canada, so it could have been like that since last October and i wouldn’t have noticed. I brought it to the dealer and they diagnosed the condenser. And then I found the TSB a few days later.
Dealer quoted about 900$ CAD for the repair. I am sure you can get it done for cheaper, but you do have to remove the front bumper to do the work i think.
I don't believe you do actually have to take the bumper off. The approach is really not all that different than changing the radiator. Both sit behind the core support. I do believe the fan needs to come out, and the radiator will need to be at least pushed back to get to the bolts holding the condenser on to the bracketry. Total pain in the rear. Not overly complicated to be real honest...but a total pain.

Good to know on the quote, I'm contemplating whether I should just have someone do it or if I should tackle it.
You can find the service manual here to see the official procedure

Note that this manual is for the Australian version. There might be a difference in the procedure because the TSB identified a difference between version with transmission cooler and those that do not have one. The Canada and US CX-9 don't have an ATF cooler, but I think the Australian CX-9 might.
Because of the environmental laws with regards to refrigerant where I live, I would not be allowed to work on it myself and refill it. So even if I did the work myself, I would still have to bring it to a shop to get it refilled after, and I don't even know if they would accept my repair at face value (because of those laws). Mazda only quotes 2.1 hours of work for it all on the TSB, so I don't know much I would actually save if I did it myself and then brought it in to a shop for them to refill the system.
Awesome, thanks for the posting the manual info! That helps if I decide to do this on my own.

I saw that in the TSB that it calls for only 2 rough hours of time, so it might just be cost effective to have someone do it and not worry about it. I just haven't had great luck with people touching this car so far.
2018 CX-9, had condenser replaced free under warranty June 2021. A/C no longer running cold, after not being used throughout last 4 or 5 months. To be serviced at dealership next few weeks. I will report what was wrong/fixed and what it cost.
Interesting to see more people kind of trickling into this thread with the same issue. So disheartening...
If you DIY, usually the oil is not lost when the gas is lost. You say that you don't see any oil, so that's good. By the way, the polyalkalene glycol oil comes in different viscosities, and the correct one for the car must be used.

You might as well change the o-ring, vacuum the system for a day to both confirm no more leaks and to evacuate all air and moisture, and recharge. If it won't hold the deep vacuum you know you still have a leak.

By the way, the trade name "Freon" hasn't been used for years and did not apply to the car's refrigerant, R-134a, which now is out of production but still available at a high price.
2018 CX-9, had condenser replaced free under warranty June 2021. A/C no longer running cold, after not being used throughout last 4 or 5 months. To be serviced at dealership next few weeks. I will report what was wrong/fixed and what it cost.
I feel fortunate, cost me 1 hour of labor at dealership rates.


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